IBM Fills 'Airgap' To Create Faster Chips

Scientists at IBM have devised a way to create vacuum spaces between copper wires in semiconductors, which could lead to chips that consume less power.
The technique creates a vacuum between copper wires on a chip, allowing electrical signals to flow faster while consuming less power. The self-assembly process enables the nanoscale patterning required to form the gaps, and this patterning is considerably smaller than current lithographic techniques can achieve.

The IBM researchers said a vacuum is the ultimate insulator for wiring capacitance, which occurs when two conductors, in this case adjacent wires on a chip, siphon electrical energy from one another, generating undesirable heat and slowing the speed at which data can move through a chip.

The process was jointly invented between IBM's Almaden Research Center (San Jose, Calif.) and the Thomas .J. Watson Research Center (Yorktown Heights, N.Y.) The technique was perfected for future commercial production at the College of Nanoscale Science and Engineering of the University at Albany. The lab also operates as part of the Albany NanoTech facilities, which has close ties to IBM. IBM's Semiconductor Research and Development Center in East Fishkill, also contributed.

IBM said a key advance in that its technology skips the masking and light-etching process. Instead, it uses the right mix of compounds, which are poured on to a silicon wafer with the wired chip patterns and then baked.

The process provides the proper environment for compounds to assemble in a directed manner, creating uniform, nanoscale holes across an entire 300-mm wafer. The holes are just 20-nm in diameter, and are said to be up to five times smaller than are typical with current lithography techniques.

Once the holes are formed, the carbon silicate glass is removed, creating a vacuum between the wires.

The IBM researchers noted that the self-assembly process is used in nature to create seashells, snowflakes and even tooth enamel.